GRAVITON AMPLITUDES, EFFECTIVE ACTION AND STRING GENERATING FUNCTIONAL ON THE DISC

1989 ◽  
Vol 04 (13) ◽  
pp. 3269-3304 ◽  
Author(s):  
A.A. TSEYTLIN
Keyword(s):  
Field Theory ◽  
String Theory ◽  
General Expression ◽  
Effective Field Theory ◽  
Effective Action ◽  
Closed String ◽  
Effective Field ◽  
Generating Functional ◽  
S Matrix ◽  
String Amplitudes

We discuss some issues related to computation and renormalization of closed string amplitudes and effective action on the disc. The general expression for the O (ln ε) term in the string theory and effective field theory generating functionals for the S matrix is found. It is emphasized that in order to establish the correspondence between the string theory and the effective field theory it is necessary to compare the total coefficients of all (“local” plus “modular” and “N-dependent” plus “N-independent”) infinities present in the amplitudes. The regularized expression for the N=3 graviton amplitude on the disc is explicitly computed and it is suggested that a proper regularization is a key to a resolution of a paradox discussed previously in the literature.

CONSISTENCY BETWEEN THE S-MATRIX AND THE SIGMA- MODEL APPROACHES TO THE CLOSED STRING EFFECTIVE ACTION ON THE DISC

1988 ◽  
Vol 03 (06) ◽  
pp. 561-569 ◽  
Author(s):  
L.V. ROZHANSKY ◽  
A.A. TSEYTLIN
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Effective Action ◽  
Sigma Model ◽  
Closed String ◽  
Effective Field ◽  
Cosmological Term ◽  
S Matrix ◽  
String Amplitudes ◽  
Closed Bosonic String

We show that a part of logarithmic divergences in the closed bosonic string amplitudes on the disc was over-looked in the previous studies. The sum of all logarithmic divergences is found to be in agreement with the “tadpole” divergences in the effective field theory with the “cosmological term” representing the disc correction. This resolves the problem raised recently by Fischler, Klebanov and Susskind.

STRING THEORY EFFECTIVE ACTION: STRING LOOP CORRECTIONS

1988 ◽  
Vol 03 (02) ◽  
pp. 365-395 ◽  
Author(s):  
A.A. TSEYTLIN
Keyword(s):  
String Theory ◽  
Effective Action ◽  
Sigma Model ◽  
Closed String ◽  
Vertex Operators ◽  
S Matrix ◽  
String Loop ◽  
String Amplitudes ◽  
Loop Amplitudes

We discuss the general ideology of the computation of string loop corrections to the effective action for the massless modes of the string. Both the S-matrix and the sigma-model approaches are presented. It is emphasized that the effective action is a more general and better defined object than the S-matrix. In particular, it is finite in spite of modular infinities that may be present in loop amplitudes computed near a “wrong” vacuum. The case of the disc topology in the open-closed string theory is treated in some detail. Some issues concerning the soft dilaton vertex operators related to the infinities of the string amplitudes are disucssed.

AMPLITUDES IN THE N=2 STRING

1991 ◽  
Vol 06 (09) ◽  
pp. 795-803 ◽  
Author(s):  
MARISA BONINI ◽  
EDI GAVA ◽  
ROBERTO IENGO
Keyword(s):  
Field Theory ◽  
String Theory ◽  
Effective Field Theory ◽  
Closed String ◽  
Space Time ◽  
Effective Field ◽  
Loop Correction ◽  
Theory Result ◽  
The One ◽  
Point Amplitude

We study the properties of amplitudes in the closed string theory based on the N=2 worldsheet supergravity. The one-loop correction to the three-point amplitude is computed and compared to the effective field theory result. We discuss the peculiar kinematics arising from the (2, 2) signature of the space-time and its role in the factorization properties of the amplitudes.

RENORMALIZATION GROUP EQUATION AND EFFECTIVE ACTION IN STRING THEORY

1989 ◽  
Vol 04 (10) ◽  
pp. 941-951 ◽  
Author(s):  
J. GAITE
Keyword(s):  
Renormalization Group ◽  
String Theory ◽  
Effective Action ◽  
Renormalization Group Equation ◽  
Group Equation ◽  
Generating Functional ◽  
S Matrix

The connection between the renormalization group for the σ-model effective action for the Polyakov string and the S-matrix generating functional for dual amplitudes is studied. A more general approach to the renormalization group equation for string theory is proposed.

scholarly journals Geometry of orientifold vacua and supersymmetry breaking

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Thibaut Coudarchet ◽  
Emilian Dudas ◽  
Hervé Partouche
Keyword(s):  
Field Theory ◽  
Supersymmetry Breaking ◽  
Effective Field Theory ◽  
Scalar Potential ◽  
Open String ◽  
Closed String ◽  
Effective Field ◽  
Internal Space ◽  
Gravitino Mass ◽  
The One

Abstract Starting from a peculiar orientifold projection proposed long ago by Angelantonj and Cardella, we elaborate on a novel perturbative scenario that involves only D-branes, together with the two types of orientifold planes O± and anti-orientifold planes $$ {\overline{\mathrm{O}}}_{\pm } $$ O ¯ ± . We elucidate the microscopic ingredients of such models, connecting them to a novel realization of brane supersymmetry breaking. Depending on the position of the D-branes in the internal space, supersymmetry can be broken at the string scale on branes, or alternatively only at the massive level. The main novelty of this construction is that it features no NS-NS disk tadpoles, while avoiding open-string instabilities. The one-loop potential, which depends on the positions of the D-branes, is minimized for maximally broken, non-linearly realized supersymmetry. The orientifold projection and the effective field theory description reveal a soft breaking of supersymmetry in the closed-string sector. In such models it is possible to decouple the gravitino mass from the value of the scalar potential, while avoiding brane instabilities.

scholarly journals EFT anomalous dimensions from the S-matrix

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Joan Elias Miró ◽  
James Ingoldby ◽  
Marc Riembau
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Form Factors ◽  
Effective Field ◽  
Higher Dimension ◽  
Powerful Method ◽  
Loop Contribution ◽  
Anomalous Dimensions ◽  
S Matrix ◽  
The Standard Model

Abstract We use the on-shell S-matrix and form factors to compute anomalous dimensions of higher dimension operators in the Standard Model Effective Field Theory. We find that in many instances, these computations are made simple by using the on-shell method. We first compute contributions to anomalous dimensions of operators at dimension-six that arise at one-loop. Then we calculate two-loop anomalous dimensions for which the corresponding one-loop contribution is absent, using this powerful method.

scholarly journals On the one-loop calculations with Reggeized quarks

2017 ◽  
Vol 32 (40) ◽  
pp. 1750207 ◽  
Author(s):  
Maxim Nefedov ◽  
Vladimir Saleev
Keyword(s):  
Field Theory ◽  
Renormalization Group ◽  
Effective Field Theory ◽  
Effective Action ◽  
Gauge Invariance ◽  
Effective Field ◽  
Loop Correction ◽  
Gauge Invariant ◽  
The One ◽  
Regge Limit

The technique of one-loop calculations for the processes involving Reggeized quarks is described in the framework of gauge invariant effective field theory for the Multi-Regge limit of QCD, which has been introduced by Lipatov and Vyazovsky. The rapidity divergences, associated with the terms enhanced by log(s), appear in the loop corrections in this formalism. The covariant procedure of regularization of rapidity divergences, preserving the gauge invariance of effective action is described. As an example application, the one-loop correction to the propagator of Reggeized quark and [Formula: see text]-scattering vertex are computed. Obtained results are used to construct the Regge limit of one-loop [Formula: see text] amplitude. The cancellation of rapidity divergences and consistency of the EFT prediction with the full QCD result is demonstrated. The rapidity renormalization group within the EFT is discussed.

scholarly journals Effective field theory for closed strings near the Hagedorn temperature

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Ram Brustein ◽  
Yoav Zigdon
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Effective Action ◽  
Equations Of Motion ◽  
Flat Space ◽  
Conformal Structure ◽  
Effective Field ◽  
Conformally Invariant ◽  
Conformal Field ◽  
Quartic Interaction

Abstract We discuss interacting, closed, bosonic and superstrings in thermal equilibrium at temperatures close to the Hagedorn temperature in flat space. We calculate S-matrix elements of the strings at the Hagedorn temperature and use them to construct a low-energy effective action for interacting strings near the Hagedorn temperature. We show, in particular, that the four-point amplitude of massless winding modes leads to a positive quartic interaction. Furthermore, the effective field theory has a generalized conformal structure, namely, it is conformally invariant when the temperature is assigned an appropriate scaling dimension. Then, we show that the equations of motion resulting from the effective action possess a winding-mode-condensate background solution above the Hagedorn temperature and present a worldsheet conformal field theory, similar to a Sine-Gordon theory, that corresponds to this solution. We find that the Hagedorn phase transition in our setup is second order, in contrast to a first-order transition that was found previously in different setups.

scholarly journals Prospects for primordial gravitational waves in string inflation

2016 ◽  
Vol 25 (12) ◽  
pp. 1644011 ◽  
Author(s):  
Susha L. Parameswaran ◽  
Ivonne Zavala
Keyword(s):  
Field Theory ◽  
String Theory ◽  
Gravitational Waves ◽  
Effective Field Theory ◽  
Effective Field ◽  
Moduli Stabilization ◽  
Slow Roll ◽  
Primordial Gravitational Waves ◽  
Difficult Challenge ◽  
String Models

Assuming that the early universe had (i) a description using perturbative string theory and its field theory limit, (ii) an epoch of slow-roll inflation within a four-dimensional effective field theory and a hierarchy of scales [Formula: see text] that keeps the latter under control, we derive an upper bound on the amplitude of primordial gravitational waves. The bound is very sensitive to mild changes in numerical coefficients and the expansion parameters. For example, allowing couplings and mass-squared hierarchies [Formula: see text] implies [Formula: see text], but asking more safely for hierarchies [Formula: see text], the bound becomes [Formula: see text]. Moreover, large volumes — typically used in string models to keep backreaction and moduli stabilization under control — drive [Formula: see text] down. Consequently, any detection of inflationary gravitational waves would present an interesting but difficult challenge for string theory.

Sign in / Sign up

Export Citation Format

Share Document